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FREDERICK MANN, or KoRorr GREEK, BRAYBROOK, NEAR MELBOURNE,

AssieNoR on TWO-THIRDS OF HIS RIGHT TO ROBERT STEELE SOUTH),-

OF "MELBOURNE, COLONY OF VICTORIA, AND THOMAS TOLLY JONES,

OF LONDON, ENGLAND.

PROCESS or MANUFACTURING NlTRO-GLYCERINE.

SPECIFIUATION forming part Of Letters Patent NO. 226,867, datedApril 27, 1880. Application filed January 23,1878.

To all whom it may concern 4 Be it known that I, FREDERICK MANN, of Koroit Creek, Braybrook, near Melbourne, in the Colony of Victoria, mannfiicturing chemist, have invented a new and useful Improvement in the Process of lllanufacturing Nitro- Glycerine, which process is fully set forth in I the following'specificatioin water It is well known that'nitro-glyccrine is man ufactured by the admixture of glycerine with nitric and sulphuric acids and the subsequent washing, away of the waste acids in very cold This water is made very cold because of the strong tendency of the nitro-glycerine to decompose except when kept at every low temperature. Notwithstanding the coldness of the water, however, thereis a considerable heat engendered immediately the acids mix with the water. This heat injuriously afl'ects the iiitro-glycerine which accompanies the acids, causing its partial decomposition and lowering its quality. 7 7 Now, my invention has been designed for the express. purpose of preventing this decomposition and lowering of the quality of the nitro-glycerine.

It consists in first crystallizing the nitroglycerine by freezing before attempting. to separate it from the acids, and then separating such crystals from such acids by a centrifugal washer, such as is used for the separation of sugar-crystals from molasses, or by any other of the machines now in use for separating crystals from liquids. y

In making nitro-glycerine according to my invention the acids and glycerine may be mixed in any one of the methods commonly employed When this has. been done my invention comes into play, for, instead of conducting such-mixture into a largequantity of very cold water, I subject it. at once to a sufiiciently low temperature to freeze orcrystallize the nitro-glycerinecontained therein,anyof the ,known processes or machines being used for that purpose. This is not readily accomplished, but it is very greatly assisted it a very small portion-say a tea spoonful-of previouslyfrozen nitroglycerine be thrown into the vessel containing the mix ure. The addition of frozen nitro-glycerine is not necessary except when making the first charge, ina'sm-uch as suificient frozen material clings to and remains on the sides of the vessel after the first charge for subsequent operations. The fact of its having frozen is known by avery sudden rise in 'the temperature of the mixture, which rise is indicated on. a thermometer attached thereto.

This r'ise will amount to several degrees say from 15 to 25--and is seen at a glance. When this has been accomplished I separate the crystallized nitro-glycerine from the waste acids by placing the whole in a centrifugal then place in cold water, when it li'quefies and sinks to the bottom, f om whence it can be drawn, and after being purified by successive washings in cold water, and lastly in a weak and cold alkaline solution, in the manner well understood, it may. be used for any purpose.

Havingthus described my invention, what I claim as new, and desire to secure by Let tors Patent, is- The described method of sep rating nitroglycerine from its acid mother liquid, consistin g, essentially, in first freezing the mixed acids and nitroglycerine, and then removing the crystallized nitro glycerine from the waste acids, snhstantiallyras described. I

Witnesses;

EDwnWuERs, W. S. 'BAYs'roN.

machine snch as is commonly used for separating crystallized sugar from molasses. The crystallized nitro-glycerine thus obtained I 

